| impromptu(adjective, adverb, simple, plain, informal) |
| spontaneous(noun, adjective, plain, impulsive, willing) |
| unrehearsed(adjective, adverb, plain, impulsive, prepared) |
| offhand(noun, adjective, simple, natural, chance) |
| unpremeditated(noun, adjective, impulsive, planned, impulse) |
| unprepared(adjective, spontaneous, unprepared, impromptu, unplanned) |
| extempore(adjective, simple, informal, natural, chance) |
| extemporary(adjective, free, casual, impulsive, prepared) |
| improvised(adjective, simple, informal, natural, chance) |
| spur-of-the-moment(noun, adjective, impulsive, prepared, spontaneous) |
| ad-lib(adjective, simple, informal, natural, casual) |
| impulsive(noun, adjective, adverb, simple, natural) |
| informal(adjective, free, plain, casual, impulsive) |
| off-the-cuff(adjective, adverb, simple, informal, natural) |
| unplanned(noun, adjective, simple, informal, natural) |
| unstudied(adjective, simple, natural, casual, impulsive) |
| ad lib(expression, adjective, idiom, adverb, impulsive) |
| casual(adjective, free, simple, natural, chance) |
| makeshift(adjective, free, simple, casual, crude) |
| off the cuff(expression, adjective, idiom, unprepared, impromptu) |